Recently, in the field of a light emitting diode (LED:Light Emitting Diode), an element used with an ultraviolet emitting diode comprising an InGaN-based material and the like are developed, and shortening of wavelength is proceeded. When a LED is used as a luminous element, the LED is usually sealed with a transparent resin.
A resin used for sealing a LED is an epoxy resin composition comprising a curative agent of an acid anhydride is general. However, when a LED was sealed with this epoxy resin composition, a crack is occurred on resin cured product by cyclic heat-cool, there have been problems in the case of using in a severe condition.
As other materials for sealing, a composition comprising acrylic resin having an alicyclic epoxy group, a cationic polymerization initiator and the like is used (cf. JP-A H02-289611). This composition leads to little deterioration by a light in sealing a LED and the like since the resin cured product does not have an aromatic ring, however, the cured product is brittler than a cured product with an acid anhydride and a crack destruction is easy to occur by cyclic heat-cool.
Therefore, it was problematic to utilize in applications using a LED that a long-time dependability was required, and the like.
In addition, a method for using a silicon-modified epoxy resin which was obtained by reacting an epoxy resin and an organopolysiloxane having a phenolic hydroxyl group to seal a LED and the like is disclosed (cf. JP-A H05-287172). According to this method, although toughness becomes higher due to being modified with silicon and a crack destruction is difficult to occur by cyclic heat-cool, ultraviolet-ray transparency is low and a resin is easy to deteriorate by an ultraviolet ray because resin has an aromatic ring.